GB318414A - Improvements in hydraulically operated indexing-mechanism for metal cutting and other machine tools - Google Patents

Abstract

318,414. National Automatic Tool Co., and Sudhoff, A. G. Oct. 17, 1928. Indexing.-In a machine-tool having an indexable work or tool carrying table, the indexing movements are effected by means of a gear which is oscillated by hydraulically-operated racks and the table is held by the hydraulic pressure in its various working positions. The table 12 has an annular bearing 14 on the frame 10 and is carried on a spindle 11 having a bearing 21 in the lower part of the frame. An upper clutch member 23 is keyed to the spindle 11 and is mounted in a bearing sleeve 25. The coacting lower clutch member 28 is slidably keyed to an oscillating gear 26 and the clutch teeth, which are of ratchet form to give a one-way drive are normally held in engagement by springs 32. The table carries stop members 37 secured by screws 39 and having flattened surfaces which coact with a flat on a spring plunger 41. The gear 26 is oscillated by racks 60, 61 which are alternately moved by hydraulic cylinders 56, 57 and one of the racks is adapted to engage a projection 49 on a bell crank lever 47, 48, to withdraw the plunger 41 at the required times. The hydraulic cylinders are supplied from a pump 66 which draws fluid from a sump 67 and delivers continuously through a pipe 70 to the cylinder 57. A further delivery pipe 71 may be connected through a valve 72 and a pipe 73 to the larger cylinder 56. In operation, when the valve is in the position shown in Fig. 5, fluid is admitted to both cylinders and the greater force exerted by the larger cylinder rotates the gear 26 in a direction to cause the table indexing movement and to hold one of the stops 37 firmly against the plunger 41. When the operation in this position is completed the valve 72 is shifted either automatically or, as shown, by means of a handle 83<1> connected to an arm 83 having a projection engaging between collars on the valve rod. A quick throw-over device consisting of a spring plunger 86 coacting with a roller is provided. This causes the cylinder 56 to be opened to exhaust while the cylinder 57 acts to return the gear 26, the clutch 28 ratcheting idly in this direction. Near the end of this movement the rack member 61 engages the pin 49 to withdraw the plunger and then acts on a pin 84 connected by an arm 82 to the lever 83, thus shifting the valve to the position shown in Fig. 5 to effect another indexing movement. Oilways are provided at 88, 89, and from the latter oil flows to a basin 90 and thence through passages 91, 92 to the table spindle bearings. In a modification, compressed air may be used in place of oil for the motive fluid and in a further modification, Fig. 7, the cylinders may be hydraulically supplied from reservoirs 91, 92 while compressed air delivered from a pump 95 and controlled by the valve 72 is selectively admitted to the reservoirs above the oil levels 93, 94.